Publication statistics
Pub. period:1994-2011
Pub. count:108
Number of co-authors:104
Co-authors
Number of publications with 3 favourite co-authors:
Tovi Grossman:14Clifton Forlines:12Gordon Kurtenbach:11 Productive colleagues
Ravin Balakrishnan's 3 most productive colleagues in number of publications:
Scott E. Hudson:113James A. Landay:91Bill Buxton:78
“
For a list of all the ways technology has failed to improve the quality of life, please press three.
”
-- Alice Kahn
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Ravin BalakrishnanPh.D
Has also published under the name of:
"R. Balakrishnan"
Personal Homepage:
http://www.dgp.toronto.edu/~ravin/Current place of employment:
University of TorontoRavin Balakrishnan is a Professor of Computer Science and Canada Research Chair in Human-Centred Interfaces at the Department of Computer Science, University of Toronto where he co-directs the Dynamic Graphics Project (DGP) laboratory. His research interests are in Human Computer Interaction (HCI), Information and Communications Technology for Development, and Interactive Computer Graphics. He earned his Ph.D. in Computer Science from the University of Toronto, working with Bill Buxton, while concurrently a part-time researcher at Alias|wavefront (now part of Autodesk). He was elected to the ACM CHI Academy in 2011, is the recipient of an Alfred P. Sloan Research Fellowship (2007), an Ontario Premier's Research Excellence Award (2003), the Bell University Laboratories Associate Chair in HCI at the University of Toronto (2002-2006), and best paper awards, nominations and honourable mentions at the CHI 2010, CSCW 2010, CHI 2009, CHI 2008, CSCW 2006, UIST 2006, CHI 2005, Graphics Interface 2005 and UIST 2004 conferences. In addition to working with students and colleagues at Toronto, he collaborates with researchers at leading industrial laboratories and universities worldwide, including stints as a visiting researcher at Mitsubishi Electric Research Laboratories (MERL) (2005-2007), a visiting professor at the University of Paris & INRIA (2006), and a visiting researcher at Microsoft Research's Redmond, Beijing, Bangalore and Cambridge labs while on sabbatical from the University of Toronto during the 2007-2008 academic year. He was a co-founder of Bump Technologies Inc., which was acquired by Google in 2010, and is involved in another startup that is commercializing research conducted in his lab: Arcestra. Further information, including publications and videos demonstrating some of his research, can be obtained from www.dgp.toronto.edu/~ravin
Publications by Ravin Balakrishnan (bibliography)
Zhao, Jian, Chevalier, Fanny and Balakrishnan, Ravin (2011): KronoMiner: using multi-foci navigation for the visual exploration of time-series data. In: Proceedings of ACM CHI 2011 Conference on Human Factors in Computing Systems 2011. pp. 1737-1746.
“The need for pattern discovery in long time-series data led researchers to develop interactive visualization tools and analytical algorithms for gaining insight into the data. Most of the literature on time-series data visualization either focus on a small number of tasks or a specific domain. We propose KronoMiner, a tool that embeds new interaction and visualization techniques as well as analytical capabilities for the visual exploration of time-series data. The interface's design has been iteratively refined based on feedback from expert users. Qualitative evaluation with an expert user not involved in the design process indicates that our prototype is promising for further research.”
© All rights reserved Zhao et al. and/or their publisher
Freeman, Dustin and Balakrishnan, Ravin (2011): Tangible actions. In: Proceedings of the 2011 ACM International Conference on Interactive Tabletops and Surfaces 2011. pp. 87-96.
“We present Tangible Actions, an ad-hoc, just-in-time, visual programming by example language designed for large multitouch interfaces. With the design of Tangible Actions, we contribute a continually-created system of programming tokens that occupy the same space as the objects they act on. Tangible Actions are created by the gestural actions of the user, and they allow the user to reuse and modify their own gestures with a lower interaction cost than the original gesture. We implemented Tangible Actions in three different tabletop applications, and ran an informal evaluation. While we found that study participants generally liked and understood Tangible Actions, having the objects and the actions co-located can lead to visual and interaction clutter.”
© All rights reserved Freeman and Balakrishnan and/or ACM Press
Jain, Mohit, Birnholtz, Jeremy, Cutrell, Edward and Balakrishnan, Ravin (2011): Exploring display techniques for mobile collaborative learning in developing regions. In: Proceedings of 13th Conference on Human-computer interaction with mobile devices and services 2011. pp. 81-90.
“The developing world faces infrastructural challenges in providing Western-style educational computing technologies, but on the other hand observes very high cell phone penetration. However, the use of mobile technology has not been extensively explored in the context of collaborative learning. New projection and display technologies for mobile devices raise the important question of whether to use single or multiple displays in these environments. In this paper, we explore two mobile-based techniques for using co-located collaborative game-play to supplement ESL (English as a Second Language) education in a developing region: (1) Mobile Single Display Groupware: a pico-projector connected to a cell phone, with a handheld controller for each child to interact, and (2) Mobile Multiple Display Groupware: a phone for each child. We explore the types of interaction that occur in both of these conditions and the impact on learning outcomes.”
© All rights reserved Jain et al. and/or ACM Press
Mathur, Akhil, Ramachandran, Divya, Cutrell, Edward and Balakrishnan, Ravin (2011): An exploratory study on the use of camera phones and pico projectors in rural India. In: Proceedings of 13th Conference on Human-computer interaction with mobile devices and services 2011. pp. 347-356.
“We explore the potential of using camera phones and pico projectors in rapid creation and presentation of digital content in a development context. A camera phone based content authoring application was designed and deployed with three different user populations in the domains of classroom education and health care. Our findings show that despite the variations in education levels, cultural background, and technology exposure, users successfully created and presented different forms of digital content using the camera phone and pico projector.”
© All rights reserved Mathur et al. and/or ACM Press
Thiel, Yannick, Singh, Karan and Balakrishnan, Ravin (2011): Elasticurves: exploiting stroke dynamics and inertia for the real-time neatening of sketched 2D curves. In: Proceedings of the 2011 ACM Symposium on User Interface Software and Technology 2011. pp. 383-392.
“Elasticurves present a novel approach to neaten sketches in real-time, resulting in curves that combine smoothness with user-intended detail. Inspired by natural variations in stroke speed when drawing quickly or with precision, we exploit stroke dynamics to distinguish intentional fine detail from stroke noise. Combining inertia and stroke dynamics, elasticurves can be imagined as the trace of a pen attached to the user by an oscillation-free elastic band. Sketched quickly, the elasticurve spatially lags behind the stroke, smoothing over stroke detail, but catches up and matches the input stroke at slower speeds. Connectors, such as lines or circular-arcs link the evolving elasticurve to the next input point, growing the curve by a responsiveness fraction along the connector. Responsiveness is calibrated, to reflect drawing skill or device noise. Elasticurves are theoretically sound and robust to variations in stroke sampling. Practically, they neaten digital strokes in real-time while retaining the modeless and visceral feel of pen on paper.”
© All rights reserved Thiel et al. and/or ACM Press
Scott, James, Izadi, Shahram, Rezai, Leila Sadat, Ruszkowski, Dominika, Bi, Xiaojun and Balakrishnan, Ravin (2010): RearType: text entry using keys on the back of a device. In: Proceedings of 12th Conference on Human-computer interaction with mobile devices and services 2010. pp. 171-180.
“RearType is a text input system for mobile devices such as Tablet PCs, using normal keyboard keys but on the reverse side of the device. The standard QWERTY layout is split and rotated so that hands gripping the device from either side have the usual keys under the fingers. This frees up the front of the device, maximizing the use of the display for visual output, eliminating the need for an onscreen keyboard and the resulting hand occlusion, and providing tactile and multi-finger text entry -- with potential for knowledge transfer from QWERTY. Using a prototype implementation which includes software visualization of the keys to assist with learning, we conducted a study to explore the initial learning curve for RearType. With one hour's training, RearType typing speed was an average 15 WPM, and was not statistically different to a touchscreen keyboard.”
© All rights reserved Scott et al. and/or their publisher
Bi, Xiaojun, Bae, Seok-Hyung and Balakrishnan, Ravin (2010): Effects of interior bezels of tiled-monitor large displays on visual search, tunnel steering, and target selection. In: Proceedings of ACM CHI 2010 Conference on Human Factors in Computing Systems 2010. pp. 65-74.
“Tiled-monitor large displays are widely used in various application domains. However, how their interior bezels affect user performance and behavior has not been fully understood. We conducted three controlled experiments to investigate effects of tiled-monitor interior bezels on visual search, straight-tunnel steering, and target selection tasks. The conclusions of our paper are: 1) interior bezels do not affect visual search time nor error rate; however, splitting objects across bezels is detrimental to search accuracy, 2) interior bezels are detrimental to straight-tunnel steering, but not to target selection. In addition, we discuss how interior bezels affect user behaviors, and suggest guidelines for effectively using tiled-monitor large displays and designing user interfaces suited to them.”
© All rights reserved Bi et al. and/or their publisher
Vogel, Daniel and Balakrishnan, Ravin (2010): Occlusion-aware interfaces. In: Proceedings of ACM CHI 2010 Conference on Human Factors in Computing Systems 2010. pp. 263-272.
“We define occlusion-aware interfaces as interaction techniques which know what area of the display is currently occluded, and use this knowledge to counteract potential problems and/or utilize the hidden area. As a case study, we describe the Occlusion-Aware Viewer, which identifies important regions hidden beneath the hand and displays them in a non-occluded area using a bubble-like callout. To determine what is important, we use an application agnostic image processing layer. For the occluded area, we use a user configurable, real-time version of Vogel et al.'s [21] geometric model. In an evaluation with a simultaneous monitoring task, we find the technique can successfully mitigate the effects of occlusion, although issues with ambiguity and stability suggest further refinements. Finally, we present designs for three other occlusion-aware techniques for pop-ups, dragging, and a hidden widget.”
© All rights reserved Vogel and Balakrishnan and/or their publisher
Dubroy, Patrick and Balakrishnan, Ravin (2010): A study of tabbed browsing among Mozilla Firefox users. In: Proceedings of ACM CHI 2010 Conference on Human Factors in Computing Systems 2010. pp. 673-682.
“We present a study which investigated how and why users of Mozilla Firefox use multiple tabs and windows during web browsing. The detailed web browsing usage of 21 participants was logged over a period of 13 to 21 days each, and was supplemented by qualitative data from diary entries and interviews. Through an examination of several measures of their tab usage, we show that our participants had a strong preference for the use of tabs rather than multiple windows. We report the reasons they cited for using tabs, and the advantages over multiple windows. We identify several common tab usage patterns which browsers could explicitly support. Finally, we look at how tab usage affects web page revisitation. Most of our participants switched tabs more often than they used the back button, making tab switching the second most important navigation mechanism in the browser, after link clicking.”
© All rights reserved Dubroy and Balakrishnan and/or their publisher
Amershi, Saleema, Morris, Meredith Ringel, Moraveji, Neema, Balakrishnan, Ravin and Toyama, Kentaro (2010): Multiple mouse text entry for single-display groupware. In: Proceedings of ACM CSCW10 Conference on Computer-Supported Cooperative Work 2010. pp. 169-178.
“A recent trend in interface design for classrooms in developing regions has many students interacting on the same display using mice. Text entry has emerged as an important problem preventing such mouse-based single-display groupware systems from offering compelling interactive activities. We explore the design space of mouse-based text entry and develop 13 techniques with novel characteristics suited to the multiple mouse scenario. We evaluated these in a 3-phase study over 14 days with 40 students in 2 developing region schools. The results show that one technique effectively balanced all of our design dimensions, another was most preferred by students, and both could benefit from augmentation to support collaborative interaction. Our results also provide insights into the factors that create an optimal text entry technique for single-display groupware systems.”
© All rights reserved Amershi et al. and/or their publisher
Yu, Chun, Shi, Yuanchun, Balakrishnan, Ravin, Meng, Xiangliang, Suo, Yue, Fan, Mingming and Qin, Yongqiang (2010): The satellite cursor: achieving MAGIC pointing without gaze tracking using multiple cursors. In: Proceedings of the 2010 ACM Symposium on User Interface Software and Technology 2010. pp. 163-172.
“We present the satellite cursor -- a novel technique that uses multiple cursors to improve pointing performance by reducing input movement. The satellite cursor associates every target with a separate cursor in its vicinity for pointing, which realizes the MAGIC (manual and gaze input cascade) pointing method without gaze tracking. We discuss the problem of visual clutter caused by multiple cursors and propose several designs to mitigate it. Two controlled experiments were conducted to evaluate satellite cursor performance in a simple reciprocal pointing task and a complex task with multiple targets of varying layout densities. Results show the satellite cursor can save significant mouse movement and consequently pointing time, especially for sparse target layouts, and that satellite cursor performance can be accurately modeled by Fitts' Law.”
© All rights reserved Yu et al. and/or their publisher
Ranjan, Abhishek, Birnholtz, Jeremy, Balakrishnan, Ravin and Lee, Dana (2010): Automatic camera control using unobtrusive vision and audio tracking. In: Proceedings of the 2010 Conference on Graphics Interface 2010. pp. 47-54.
“While video can be useful for remotely attending and archiving meetings, the video itself is often dull and difficult to watch. One key reason for this is that, except in very high-end systems, little attention has been paid to the production quality of the video being captured. The video stream from a meeting often lacks detail and camera shots rarely change unless a person is tasked with operating the camera. This stands in stark contrast to live television, where a professional director creates engaging video by juggling multiple cameras to provide a variety of interesting views. In this paper, we applied lessons from television production to the problem of using automated camera control and selection to improve the production quality of meeting video. In an extensible and robust approach, our system uses off-the-shelf cameras and microphones to unobtrusively track the location and activity of meeting participants, control three cameras, and cut between these to create video with a variety of shots and views, in real-time. Evaluation by users and independent coders suggests promising initial results and directions for future work.”
© All rights reserved Ranjan et al. and/or their publisher
Birnholtz, Jeremy, Ranjan, Abhishek and Balakrishnan, Ravin (2010): Providing Dynamic Visual Information for Collaborative Tasks: Experiments With Automatic Camera Control. In Human Computer Interaction, 25 (3) pp. 261-287.
“One possibility presented by novel communication technologies is the ability for remotely located experts to provide guidance to others who are performing difficult technical tasks in the real world, such as medical procedures or engine repair. In these scenarios, video views and other visual information seem likely to be useful in the ongoing negotiation of shared understanding, or common ground, but actual results with experimental systems have been mixed. One difficulty in designing these systems is achieving a balance between close-up shots that allow for discussion of detail and wide shots that allow for orientation or establishing a mutual point of focus in a larger space. Achieving this balance can be difficult without disorienting or overloading task participants. In this article we present results from two experiments involving three automated camera control systems for remote repair tasks. Results show that a system providing both detailed and overview information was superior to systems providing only one or the other in terms of performance but that some participants preferred the detail-only system.”
© All rights reserved Birnholtz et al. and/or Lawrence Erlbaum
Vogel, Daniel and Balakrishnan, Ravin (2010): Direct Pen Interaction With a Conventional Graphical User Interface. In Human Computer Interaction, 25 (4) pp. 324-388.
“We examine the usability and performance of Tablet PC direct pen input with a conventional graphical user interface (GUI). We use a qualitative observational study design with 16 participants divided into 4 groups: 1 mouse group for a baseline control and 3 Tablet PC groups recruited according to their level of experience. The study uses a scripted scenario of realistic tasks and popular office applications designed to exercise standard GUI components and cover typical interactions such as parameter selection, object manipulation, text selection, and ink annotation. We capture a rich set of logging data including 3D motion capture, video taken from the participants' point-of-view, screen capture video, and pen events such as movement and taps. To synchronize, segment, and annotate these logs, we used our own custom analysis software. We find that pen participants make more errors, perform inefficient movements, and express frustration during many tasks. Our observations reveal overarching problems with direct pen input: poor precision when tapping and dragging, errors caused by hand occlusion, instability and fatigue due to ergonomics and reach, cognitive differences between pen and mouse usage, and frustration due to limited input capabilities. We believe these to be the primary causes of nontext errors, which contribute to user frustration when using a pen with a conventional GUI. Finally, we discuss how researchers could address these issues without sacrificing the consistency of current GUIs and applications by making improvements at three levels: hardware, base interaction, and widget behavior.”
© All rights reserved Vogel and Balakrishnan and/or Lawrence Erlbaum
Vogel, Daniel, Cudmore, Matthew, Casiez, Géry, Balakrishnan, Ravin and Keliher, Liam (2009): Hand occlusion with tablet-sized direct pen input. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 557-566.
“We present results from an experiment examining the area occluded by the hand when using a tablet-sized direct pen input device. Our results show that the pen, hand, and forearm can occlude up to 47% of a 12 inch display. The shape of the occluded area varies between participants due to differences in pen grip rather than simply anatomical differences. For the most part, individuals adopt a consistent posture for long and short selection tasks. Overall, many occluded pixels are located higher relative to the pen than previously thought. From the experimental data, a five-parameter scalable circle and pivoting rectangle geometric model is presented which captures the general shape of the occluded area relative to the pen position. This model fits the experimental data much better than the simple bounding box model often used implicitly by designers. The space of fitted parameters also serves to quantify the shape of occlusion. Finally, an initial design for a predictive version of the model is discussed.”
© All rights reserved Vogel et al. and/or ACM Press
Bi, Xiaojun and Balakrishnan, Ravin (2009): Comparing usage of a large high-resolution display to single or dual desktop displays for daily work. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 1005-1014.
“With the ever increasing amount of digital information, users desire more screen real estate to process their daily computing work, and might well benefit from using a wall-size large high-resolution display instead of a desktop one. Unfortunately, we know very little about users' behaviors when using such a display for daily computing. We present a week-long study that investigates large display use in a personal desktop computing context by comparing it with single and dual desktop monitor use. Results show users' unanimous preference for using a large display: it facilitates multi-window and rich information tasks, enhances users' awareness of peripheral applications, and offers a more immersive experience. Further, the data reveals distinct usage patterns in partitioning screen real estate and managing windows on a large display. Detailed analysis of these results provides insights into designing interaction techniques and window management systems more suited to a large display.”
© All rights reserved Bi and Balakrishnan and/or ACM Press
Forlines, Clifton and Balakrishnan, Ravin (2009): Improving visual search with image segmentation. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 1093-1102.
“People's ability to accurately locate target objects in images is severely affected by the prevalence of the sought objects. This negative effect greatly impacts critical real world tasks, such as baggage screening and cell slide pathology, in which target objects are rare. We present three novel image presentation techniques that are designed to improve visual search. Our techniques rely on the images being broken into image segments, which are then recombined or displayed in novel ways. The techniques and their underlying design reasoning are described in detail, and three experiments are presented that provide initial evidence that these techniques lead to better search performance in a simulated cell slide pathology task.”
© All rights reserved Forlines and Balakrishnan and/or ACM Press
Findlater, Leah, Balakrishnan, Ravin and Toyama, Kentaro (2009): Comparing semiliterate and illiterate users' ability to transition from audio+text to text-only interaction. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 1751-1760.
“Multimodal interfaces with little or no text have been shown to be useful for users with low literacy. However, this research has not differentiated between the needs of the fully illiterate and semiliterate -- those who have basic literacy but cannot read and write fluently. Text offers a fast and unambiguous mode of interaction for literate users and the exposure to text may allow for incidental improvement of reading skills. We conducted two studies that explore how semiliterate users with very little education might benefit from a combination of text and audio as compared to illiterate and literate users. Results show that semiliterate users reduced their use of audio support even during the first hour of use and over several hours this reduction was accompanied by a gain in visual word recognition; illiterate users showed no similar improvement. Semiliterate users should thus be treated differently from illiterate users in interface design.”
© All rights reserved Findlater et al. and/or ACM Press
Hinckley, Ken, Dixon, Morgan, Sarin, Raman, Guimbretiere, Francois and Balakrishnan, Ravin (2009): Codex: a dual screen tablet computer. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 1933-1942.
“The Codex is a dual-screen tablet computer, about the size of a 4"x 6 day planner, with a self-supporting binding and embedded sensors. The device can be oriented in a variety of postures to support different nuances of individual work, ambient display, or collaboration with another user. In the context of a pen-operated note taking application, we demonstrate interaction techniques that support a fluid division of labor for tasks and information across the two displays while minimizing disruption to the primary experience of authoring notes.”
© All rights reserved Hinckley et al. and/or ACM Press
Moraveji, Neema, Inkpen, Kori, Cutrell, Ed and Balakrishnan, Ravin (2009): A mischief of mice: examining children's performance in single display groupware systems with 1 to 32 mice. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 2157-2166.
“Mischief is a system for classroom interaction that allows multiple children to use individual mice and cursors to interact with a single large display [20]. While the system can support large groups of children, it is unclear how children's performance is affected as group size increases. We explore this question via a study involving two tasks, with children working in group sizes ranging from 1 to 32. The first required reciprocal selection of two on-screen targets, resembling a swarm pointing scenario that might be used in educational applications. The second, a more temporally and spatially distributed pointing task, had children entering different words by selecting characters on an on-screen keyboard. Results indicate that performance is significantly affected by group size only when targets are small. Further, group size had a smaller effect when pointing was spatially and temporally distributed than when everyone was concurrently aiming at the same targets.”
© All rights reserved Moraveji et al. and/or ACM Press
Chu, Gerry, Moscovich, Tomer and Balakrishnan, Ravin (2009): Haptic conviction widgets. In: Proceedings of the 2009 Conference on Graphics Interface 2009. pp. 207-210.
“We introduce a haptic mousewheel as a platform for design exploration of haptic conviction widgets. Conviction is how strongly one wants to do something, or how strongly one desires a parameter to be as it is. Using the haptic mousewheel, the widgets allow users to communicate conviction using force, where greater conviction requires greater force. These widgets include buttons that take varying amounts of force to click, a trash can that requires overcoming force to delete files, an instant message client that requires more force to communicate a stronger emotion, and widgets that allow parameters to be locked using force.”
© All rights reserved Chu et al. and/or their publisher
Bae, Seok-Hyung, Balakrishnan, Ravin and Singh, Karan (2009): EverybodyLovesSketch: 3D sketching for a broader audience. In: Proceedings of the ACM Symposium on User Interface Software and Technology 2009. pp. 59-68.
“We present EverybodyLovesSketch, a gesture-based 3D curve sketching system for rapid ideation and visualization of 3D forms, aimed at a broad audience. We first analyze traditional perspective drawing in professional practice. We then design a system built upon the paradigm of ILoveSketch, a 3D curve drawing system for design professionals. The new system incorporates many interaction aspects of perspective drawing with judicious automation to enable novices with no perspective training to proficiently create 3D curve sketches. EverybodyLovesSketch supports a number of novel interactions: tick-based sketch plane selection, single view definition of arbitrary extrusion vectors, multiple extruded surface sketching, copy-and-project of 3D curves, freeform surface sketching, and an interactive perspective grid. Finally, we present a study involving 49 high school students (with no formal artistic training) who each learned and used the system over 11 days, which provides detailed insights into the popularity, power and usability of the various techniques, and shows our system to be easily learnt and effectively used, with broad appeal.”
© All rights reserved Bae et al. and/or their publisher
Saponas, T. Scott, Tan, Desney S., Morris, Dan, Balakrishnan, Ravin, Turner, Jim and Landay, James A. (2009): Enabling always-available input with muscle-computer interfaces. In: Proceedings of the ACM Symposium on User Interface Software and Technology 2009. pp. 167-176.
“Previous work has demonstrated the viability of applying offline analysis to interpret forearm electromyography (EMG) and classify finger gestures on a physical surface. We extend those results to bring us closer to using muscle-computer interfaces for always-available input in real-world applications. We leverage existing taxonomies of natural human grips to develop a gesture set covering interaction in free space even when hands are busy with other objects. We present a system that classifies these gestures in real-time and we introduce a bi-manual paradigm that enables use in interactive systems. We report experimental results demonstrating four-finger classification accuracies averaging 79% for pinching, 85% while holding a travel mug, and 88% when carrying a weighted bag. We further show generalizability across different arm postures and explore the tradeoffs of providing real-time visual feedback.”
© All rights reserved Saponas et al. and/or their publisher
Balakrishnan, Ravin and Baudisch, Patrick (2009): Introduction to this Special Issue on Ubiquitous Multi-Display Environments. In Human-Computer Interaction, 24 (1) pp. 1-8.
Ranjan, Abhishek, Birnholtz, Jeremy and Balakrishnan, Ravin (2008): Improving meeting capture by applying television production principles with audio and motion detection. In: Proceedings of ACM CHI 2008 Conference on Human Factors in Computing Systems April 5-10, 2008. pp. 227-236.
“Video recordings of meetings are often monotonous and tedious to watch. In this paper, we report on the design, implementation and evaluation of an automated meeting capture system that applies television production principles to capture and present videos of small group meetings in a compelling manner. The system uses inputs from a motion capture system and microphones to drive multiple pan-tilt-zoom cameras and uses heuristics to frame shots and cut between them. An evaluation of the system indicates that its performance approaches that of a professional crew while requiring significantly fewer human resources.”
© All rights reserved Ranjan et al. and/or ACM Press
Dragicevic, Pierre, Ramos, Gonzalo, Bibliowitcz, Jacobo, Nowrouzezahrai, Derek, Balakrishnan, Ravin and Singh, Karan (2008): Video browsing by direct manipulation. In: Proceedings of ACM CHI 2008 Conference on Human Factors in Computing Systems April 5-10, 2008. pp. 237-246.
“We present a method for browsing videos by directly dragging their content. This method brings the benefits of direct manipulation to an activity typically mediated by widgets. We support this new type of interactivity by: 1) automatically extracting motion data from videos; and 2) a new technique called relative flow dragging that lets users control video playback by moving objects of interest along their visual trajectory. We show that this method can outperform the traditional seeker bar in video browsing tasks that focus on visual content rather than time.”
© All rights reserved Dragicevic et al. and/or ACM Press
Grossman, Tovi and Balakrishnan, Ravin (2008): Collaborative interaction with volumetric displays. In: Proceedings of ACM CHI 2008 Conference on Human Factors in Computing Systems April 5-10, 2008. pp. 383-392.
“Volumetric displays possess a number of unique properties which potentially make them particularly suitable for collaborative 3D applications. Because such displays have only recently become available, interaction techniques for collaborative usage have yet to be explored. In this paper, we initiate this exploration. We present a prototype collaborative 3D model viewing application, which served as a platform for our explorations. We outline three design goals, discuss the key interaction issues which were encountered, and describe a suite of new techniques in detail. In initial user observation sessions, we found that our techniques allowed users to successfully complete a variety of 3D tasks. Furthermore, interviews with experts in potential usage domains indicated that the techniques we developed can serve as a baseline for future collaborative applications for volumetric displays.”
© All rights reserved Grossman and Balakrishnan and/or ACM Press
Saponas, T. Scott, Tan, Desney S., Morris, Dan and Balakrishnan, Ravin (2008): Demonstrating the feasibility of using forearm electromyography for muscle-computer interfaces. In: Proceedings of ACM CHI 2008 Conference on Human Factors in Computing Systems April 5-10, 2008. pp. 515-524.
“We explore the feasibility of muscle-computer interfaces (muCIs): an interaction methodology that directly senses and decodes human muscular activity rather than relying on physical device actuation or user actions that are externally visible or audible. As a first step towards realizing the mu-CI concept, we conducted an experiment to explore the potential of exploiting muscular sensing and processing technologies for muCIs. We present results demonstrating accurate gesture classification with an off-the-shelf electromyography (EMG) device. Specifically, using 10 sensors worn in a narrow band around the upper forearm, we were able to differentiate position and pressure of finger presses, as well as classify tapping and lifting gestures across all five fingers. We conclude with discussion of the implications of our results for future muCI designs.”
© All rights reserved Saponas et al. and/or ACM Press
Forlines, Clifton and Balakrishnan, Ravin (2008): Evaluating tactile feedback and direct vs. indirect stylus input in pointing and crossing selection tasks. In: Proceedings of ACM CHI 2008 Conference on Human Factors in Computing Systems April 5-10, 2008. pp. 1563-1572.
“We present a pair of experiments that explore the effects of tactile-feedback and direct vs. indirect pen input on pointing and crossing selection tasks. While previous work has demonstrated the validity of crossing as a useful selection mechanism for pen-based computing, those experiments were conducted using an indirect input device -- one in which the pen-input and display were separated. We investigate users' performance with pointing and crossing interfaces controlled via not only an indirect input device, but also a direct input device -- one in which the pen-input and display are co-located. Results show that direct input significantly outperforms indirect input for crossing selection, but the two modalities are essentially equivalent in pointing selection. A small amount of tactile feedback is shown to be beneficial for both pointing and crossing selection, most noticeably in crossing tasks when using direct input where visual feedback is often occluded by a hand or stylus.”
© All rights reserved Forlines and Balakrishnan and/or ACM Press
Cao, Xiang, Li, Jacky Jie and Balakrishnan, Ravin (2008): Peephole pointing: modeling acquisition of dynamically revealed targets. In: Proceedings of ACM CHI 2008 Conference on Human Factors in Computing Systems April 5-10, 2008. pp. 1699-1708.
“Peephole interaction occurs when a spatially aware display is moved and acts as a viewport to reveal different parts of the virtual space that cannot all fit within the display at once. We investigate pointing within this peephole metaphor, where the targets may not be initially visible on the display, but are dynamically revealed by moving the display. We develop and experimentally validate a quantitative model for peephole pointing. Our results indicate that the model accurately accounts for peephole pointing for a variety of display sizes, both with and without users' having prior knowledge of the target location.”
© All rights reserved Cao et al. and/or ACM Press
Cao, Xiang, Massimi, Michael and Balakrishnan, Ravin (2008): Flashlight jigsaw: an exploratory study of an ad-hoc multi-player game on public displays. In: Proceedings of ACM CSCW08 Conference on Computer-Supported Cooperative Work 2008. pp. 77-86.
“As large displays become prevalent in public spaces, they could be employed to create novel game experiences for the public. We present an exploratory study of an ad-hoc multi-player game played on such public displays. The game, Flashlight Jigsaw, was deployed in a shared lab space and a public atrium for two weeks in total. Through interviews supported by observations and system logs we explored the experiences and behaviors of players and spectators. We also investigated the interrelationship between public display games and the spaces they are deployed in. The research resulted in findings regarding game play, communication, social interaction, spectatorship, and space and location around such a game. We use our findings to develop design implications for future public display games.”
© All rights reserved Cao et al. and/or ACM Press
Cao, Xiang, Wilson, Andrew D., Balakrishnan, Ravin, Hinckley, Ken and Hudson, Scott E. (2008): ShapeTouch: Leveraging contact shape on interactive surfaces. In: Third IEEE International Workshop on Tabletops and Interactive Surfaces Tabletop 2008 October 1-3, 2008, Amsterdam, The Netherlands. pp. 129-136.
Casiez, Géry, Vogel, Daniel, Balakrishnan, Ravin and Cockburn, Andy (2008): The Impact of Control-Display Gain on User Performance in Pointing Tasks. In Human-Computer Interaction, 23 (3) pp. 215-250.
“We theoretically and empirically examine the impact of control display (CD) gain on mouse pointing performance. Two techniques for modifying CD gain are considered: constant gain (CG) where CD gain is uniformly adjusted by a constant multiplier, and pointer acceleration (PA) where CD gain is adjusted using a nonuniform function depending on movement characteristics. Both CG and PA are evaluated at various levels of relationship between mouse and cursor movement: from low levels, which have a near one-to-one mapping, through to high levels that aggressively amplify mouse movement. We further derive a model predicting the modification in motor-space caused by pointer acceleration. Experiments are then conducted on a standard desktop display and on a very large high-resolution display, allowing us to measure performance in high index of difficulty tasks where the effect of clutching may be pronounced. The evaluation apparatus was designed to minimize device quantization effects and used accurate 3D motion tracking equipment to analyze users' limb movements. On both displays, and in both gain techniques, we found that low levels of CD gain had a marked negative effect on performance, largely because of increased clutching and maximum limb speeds. High gain levels had relatively little impact on performance, with only a slight increase in time when selecting very small targets at high levels of constant gain. On the standard desktop display, pointer acceleration resulted in 3.3% faster pointing than constant gain and up to 5.6% faster with small targets. This supported the theoretical prediction of motor-space modification but fell short of the theoretical potential, possibly because PA caused an increase in target overshooting. Both techniques were accurately modeled by Fitts' law in all gain settings except for when there was a significant amount of clutching. From our results, we derive a usable range of CD gain settings between thresholds of speed and accuracy given the capabilities of a pointing device, display, and the expected range of target widths and distances.”
© All rights reserved Casiez et al. and/or Taylor and Francis
Prasad, Archana, Medhi, Indrani, Toyama, Kentaro and Balakrishnan, Ravin (2008): Exploring the feasibility of video mail for illiterate users. In: Levialdi, Stefano (ed.) AVI 2008 - Proceedings of the working conference on Advanced Visual Interfaces May 28-30, 2008, Napoli, Italy. pp. 103-110.
Bi, Xiaojun, Moscovich, Tomer, Ramos, Gonzalo, Balakrishnan, Ravin and Hinckley, Ken (2008): An exploration of pen rolling for pen-based interaction. In: Cousins, Steve B. and Beaudouin-Lafon, Michel (eds.) Proceedings of the 21st Annual ACM Symposium on User Interface Software and Technology October 19-22, 2008, Monterey, CA, USA. pp. 191-200.
Benko, Hrvoje, Wilson, Andrew D. and Balakrishnan, Ravin (2008): Sphere: multi-touch interactions on a spherical display. In: Cousins, Steve B. and Beaudouin-Lafon, Michel (eds.) Proceedings of the 21st Annual ACM Symposium on User Interface Software and Technology October 19-22, 2008, Monterey, CA, USA. pp. 77-86.
Bae, Seok-Hyung, Balakrishnan, Ravin and Singh, Karan (2008): ILoveSketch: as-natural-as-possible sketching system for creating 3d curve models. In: Cousins, Steve B. and Beaudouin-Lafon, Michel (eds.) Proceedings of the 21st Annual ACM Symposium on User Interface Software and Technology October 19-22, 2008, Monterey, CA, USA. pp. 151-160.
Schmidt, Ryan, Singh, Karan and Balakrishnan, Ravin (2008): Sketching and Composing Widgets for 3D Manipulation. In Comput. Graph. Forum, 27 (2) pp. 301-310.
Birnholtz, Jeremy P., Grossman, Tovi, Mak, Clarissa and Balakrishnan, Ravin (2007): An exploratory study of input configuration and group process in a negotiation task using a large display. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 91-100.
“This paper reports on an exploratory study of the effects of input configuration on group behavior and performance in a collaborative task performed by a collocated group using a large display. Twelve groups completed a mixed-motive negotiation task under two conditions: a single, shared mouse and one mouse per person. Results suggest that the multiple mouse condition allowed for more parallel work, but the quality of discussion was higher in the single mouse condition. Moreover, participants were more likely to act in their own best interest in the multiple mouse condition.”
© All rights reserved Birnholtz et al. and/or ACM Press
Grossman, Tovi, Kong, Nicholas and Balakrishnan, Ravin (2007): Modeling pointing at targets of arbitrary shapes. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 463-472.
“We investigate pointing at graphical targets of arbitrary shapes. We first describe a previously proposed probabilistic Fitts' law model [7] which, unlike previous models that only account for rectangular targets, has the potential to handle arbitrary shapes. Three methods of defining the centers of arbitrarily shaped targets for use within the model are developed. We compare these methods of defining target centers, and validate the model using a pointing experiment in which the targets take on various shapes. Results show that the model can accurately account for the varying target shapes. We discuss the implications of our results to interface design.”
© All rights reserved Grossman et al. and/or ACM Press
Wigdor, Daniel, Shen, Chia, Forlines, Clifton and Balakrishnan, Ravin (2007): Perception of elementary graphical elements in tabletop and multi-surface environments. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 473-482.
“Information shown on a tabletop display can appear distorted when viewed by a seated user. Even worse, the impact of this distortion is different depending on the location of the information on the display. In this paper, we examine how this distortion affects the perception of the basic graphical elements of information visualization shown on displays at various angles. We first examine perception of these elements on a single display, and then compare this to perception across displays, in order to evaluate the effectiveness of various elements for use in a tabletop and multi-display environment. We found that the perception of some graphical elements is more robust to distortion than others. We then develop recommendations for building data visualizations for these environments.”
© All rights reserved Wigdor et al. and/or ACM Press
Grossman, Tovi, Wigdor, Daniel and Balakrishnan, Ravin (2007): Exploring and reducing the effects of orientation on text readability in volumetric displays. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 483-492.
“Volumetric displays, which provide a 360° view of imagery illuminated in true 3D space, are a promising platform for interactive 3D applications. However, presenting text in volumetric displays can be a challenge, as the text may not be oriented towards the user. This is especially problematic with multiple viewers, as the text could, for example, appear forwards to one user, and backwards to another. In a first experiment we determined the effects of 3D rotations on text readability. Based on the results, we developed and evaluated a new technique which optimizes text orientation for multiple viewers. This technique provided 33% faster group reading times in a collaborative experimental task.”
© All rights reserved Grossman et al. and/or ACM Press
Forlines, Clifton, Wigdor, Daniel, Shen, Chia and Balakrishnan, Ravin (2007): Direct-touch vs. mouse input for tabletop displays. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 647-656.
“We investigate the differences -- in terms of both quantitative performance and subjective preference -- between direct-touch and mouse input for unimanual and bimanual tasks on tabletop displays. The results of two experiments show that for bimanual tasks performed on tabletops, users benefit from direct-touch input. However, our results also indicate that mouse input may be more appropriate for a single user working on tabletop tasks requiring only single-point interaction.”
© All rights reserved Forlines et al. and/or ACM Press
Ramos, Gonzalo, Cockburn, Andy, Balakrishnan, Ravin and Beaudouin-Lafon, Michel (2007): Pointing lenses: facilitating stylus input through visual-and motor-space magnification. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 757-766.
“Using a stylus on a tablet computer to acquire small targets can be challenging. In this paper we present pointing lenses -- interaction techniques that help users acquire and select targets by presenting them with an enlarged visual and interaction area. We present and study three pointing lenses for pen-based systems and find that our proposed Pressure-Activated Lens is the top overall performer in terms of speed, accuracy and user preference. In addition, our experimental results not only show that participants find all pointing lenses beneficial for targets smaller than 5 pixels, but they also suggest that this benefit may extend to larger targets as well.”
© All rights reserved Ramos et al. and/or ACM Press
Ranjan, Abhishek, Birnholtz, Jeremy P. and Balakrishnan, Ravin (2007): Dynamic shared visual spaces: experimenting with automatic camera control in a remote repair task. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 1177-1186.
“We present an experimental study of automatic camera control in the performance of collaborative remote repair tasks using video-mediated communication. Twelve pairs of participants, one "helper" and one "worker," completed a series of Lego puzzle tasks using both a static camera and an automatic camera system that was guided in part by tracking the worker's hand position. Results show substantial performance benefits for the automatic system, particularly for complex tasks. The implications of these results are discussed, along with some lessons for the use of motion tracking as a driver for camera control.”
© All rights reserved Ranjan et al. and/or ACM Press
Ramos, Gonzalo A. and Balakrishnan, Ravin (2007): Pressure marks. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 1375-1384.
“Selections and actions in GUI's are often separated -- i.e. an action or command typically follows a selection. This sequence imposes a lower bound on the interaction time that is equal to or greater than the sum of its parts. In this paper, we introduce pressure marks -- pen strokes where the variations in pressure make it possible to indicate both a selection and an action simultaneously. We propose a series of design guidelines from which we develop a set of four basic types of pressure marks. We first assess the viability of this set through an exploratory study that looks at the way users draw straight and lasso pressure marks of different sizes and orientations. We then present the results of a quantitative experiment that shows that users perform faster selection-action interactions with pressure marks than with a combination of lassos and pigtails. Based on these results, we present and discuss a number of interaction designs that incorporate pressure marks.”
© All rights reserved Ramos and Balakrishnan and/or ACM Press
Zhao, Shengdong, Dragicevic, Pierre, Chignell, Mark, Balakrishnan, Ravin and Baudisch, Patrick (2007): Earpod: eyes-free menu selection using touch input and reactive audio feedback. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 1395-1404.
“We present the design and evaluation of earPod: an eyes-free menu technique using touch input and reactive auditory feedback. Studies comparing earPod with an iPod-like visual menu technique on reasonably-sized static menus indicate that they are comparable in accuracy. In terms of efficiency (speed), earPod is initially slower, but outperforms the visual technique within 30 minutes of practice. Our results indicate that earPod is potentially a reasonable eyes-free menu technique for general use, and is a particularly exciting technique for use in mobile device interfaces.”
© All rights reserved Zhao et al. and/or ACM Press
Grossman, Tovi, Dragicevic, Pierre and Balakrishnan, Ravin (2007): Strategies for accelerating on-line learning of hotkeys. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 1591-1600.
“Hotkeys are extremely useful in leveraging expert performance, but learning them is a slow process. This paper investigates alternative menu designs that can motivate and help users remember associations between menu commands and hotkeys. Building upon previous work on paired-associate learning, we suggest that the transition to expert use can be accelerated by manipulating feedback and cost associated with menu selection. We evaluate five designs in a pilot study and then two of the most promising ones in a formal experiment, showing that the speed of hotkey learning can indeed be significantly increased with little modifications to the standard menu/hotkey paradigm.”
© All rights reserved Grossman et al. and/or ACM Press
Cao, Xiang, Forlines, Clifton and Balakrishnan, Ravin (2007): Multi-user interaction using handheld projectors. In: Proceedings of the ACM Symposium on User Interface Software and Technology October 7-10, 2007, Newport, Rhode Island, USA. pp. 43-52.
“Recent research on handheld projector interaction has expanded the display and interaction space of handheld devices by projecting information onto the physical environment around the user, but has mainly focused on single-user scenarios. We extend this prior single-user research to co-located multi-user interaction using multiple handheld projectors. We present a set of interaction techniques for supporting co-located collaboration with multiple handheld projectors, and discuss application scenarios enabled by them.”
© All rights reserved Cao et al. and/or ACM Press
Wigdor, Daniel, Shen, Chia, Forlines, Clifton and Balakrishnan, Ravin (2006): Effects of display position and control space orientation on user preference and performance. In: Proceedings of ACM CHI 2006 Conference on Human Factors in Computing Systems 2006. pp. 309-318.
“In many environments, it is often the case that input is made to displays that are positioned non-traditionally relative to one or more users. This typically requires users to perform interaction tasks under transformed input-display spatial mappings, and the literature is unclear as to how such transformations affect performance. We present two experiments that explore the impact of display space position and input control space orientation on user's subjective preference and objective performance in a docking task. Our results provide guidelines as to optimal display placement and control orientation in collaborative computing environments with one or more shared displays.”
© All rights reserved Wigdor et al. and/or ACM Press
Ranjan, Abhishek, Balakrishnan, Ravin and Chignell, Mark (2006): Searching in audio: the utility of transcripts, dichotic presentation, and time-compression. In: Proceedings of ACM CHI 2006 Conference on Human Factors in Computing Systems 2006. pp. 721-730.
“Searching audio data can potentially be facilitated by the use of automatic speech recognition (ASR) technology to generate text transcripts which can then be easily queried. However, since current ASR technology cannot reliably generate 100% accurate transcripts, additional techniques for fluid browsing and searching of the audio itself are required. We explore the impact of transcripts of various qualities, dichotic presentation, and time-compression on an audio search task. Results show that dichotic presentation and reasonably accurate transcripts can assist in the search process, but suggest that time-compression and low accuracy transcripts should be used carefully.”
© All rights reserved Ranjan et al. and/or ACM Press
Grossman, Tovi, Hinckley, Ken, Baudisch, Patrick, Agrawala, Maneesh and Balakrishnan, Ravin (2006): Hover widgets: using the tracking state to extend the capabilities of pen-operated devices. In: Proceedings of ACM CHI 2006 Conference on Human Factors in Computing Systems 2006. pp. 861-870.
“We present Hover Widgets, a new technique for increasing the capabilities of pen-based interfaces. Hover Widgets are implemented by using the pen movements above the display surface, in the tracking state. Short gestures while hovering, followed by a pen down, access the Hover Widgets, which can be used to activate localized interface widgets. By using the tracking state movements, Hover Widgets create a new command layer which is clearly distinct from the input layer of a pen interface. In a formal experiment Hover Widgets were found to be faster than a more traditional command activation technique, and also reduced errors due to divided attention.”
© All rights reserved Grossman et al. and/or ACM Press
Agarawala, Anand and Balakrishnan, Ravin (2006): Keepin' it real: pushing the desktop metaphor with physics, piles and the pen. In: Proceedings of ACM CHI 2006 Conference on Human Factors in Computing Systems 2006. pp. 1283-1292.
“We explore making virtual desktops behave in a more physically realistic manner by adding physics simulation and using piling instead of filing as the fundamental organizational structure. Objects can be casually dragged and tossed around, influenced by physical characteristics such as friction and mass, much like we would manipulate lightweight objects in the real world. We present a prototype, called BumpTop, that coherently integrates a variety of interaction and visualization techniques optimized for pen input we have developed to support this new style of desktop organization.”
© All rights reserved Agarawala and Balakrishnan and/or ACM Press
Forlines, Clifton, Shen, Chia, Wigdor, Daniel and Balakrishnan, Ravin (2006): Exploring the effects of group size and display configuration on visual search. In: Proceedings of ACM CSCW06 Conference on Computer-Supported Cooperative Work 2006. pp. 11-20.
“Visual search is the subject of countless psychology studies in which people search for target items within a scene. The bulk of this literature focuses on the individual with the goal of understanding the human perceptual system. In life, visual search is performed not only by individuals, but also by groups -- a team of doctors may study an x-ray and a team of analysts may study a satellite photograph. In this paper, we examine the issues one should consider when searching as a group. We present the details of an experiment designed to investigate the impact of group size on visual search performance, and how different display configurations affected that performance. We asked individuals, pairs, and groups of four people to participate in a baggage screening task in which these teams searched simulated x-rays for prohibited items. Teams conducted these searches on single monitors, a row of four monitors, and on a single horizontal display. Our findings suggest that groups commit far fewer errors in visual search tasks, although they may perform slower than individuals under certain conditions. The interaction between group size and display configuration turned out to be an important factor as well.”
© All rights reserved Forlines et al. and/or ACM Press
Ranjan, Abhishek, Birnholtz, Jeremy P. and Balakrishnan, Ravin (2006): An exploratory analysis of partner action and camera control in a video-mediated collaborative task. In: Proceedings of ACM CSCW06 Conference on Computer-Supported Cooperative Work 2006. pp. 403-412.
“This paper reports on an exploratory experimental study of the relationships between physical movement and desired visual information in the performance of video-mediated collaborative tasks in the real world by geographically distributed groups. Twenty-three pairs of participants (one "helper" and one "worker") linked only by video and audio participated in a Lego construction task in one of three experimental conditions: a fixed scene camera, a helper-controlled pan-tilt-zoom camera, and a dedicated operator-controlled camera. "Worker" motion was tracked in 3-D space for all three conditions, as were all camera movements. Results suggest performance benefits for the operator-controlled condition, and the relationships between camera position/movement and worker action are explored to generate preliminary theoretical and design implications.”
© All rights reserved Ranjan et al. and/or ACM Press
Grossman, Tovi and Balakrishnan, Ravin (2006): The design and evaluation of selection techniques for 3D volumetric displays. In: Proceedings of the ACM Symposium on User Interface Software and Technology 2006. pp. 3-12.
“Volumetric displays, which display imagery in true 3D space, are a promising platform for the display and manipulation of 3D data. To fully leverage their capabilities, appropriate user interfaces and interaction techniques must be designed. In this paper, we explore 3D selection techniques for volumetric displays. In a first experiment, we find a ray cursor to be superior to a 3D point cursor in a single target environment. To address the difficulties associated with dense target environments we design four new ray cursor techniques which provide disambiguation mechanisms for multiple intersected targets. Our techniques showed varied success in a second, dense target experiment. One of the new techniques, the depth ray, performed particularly well, significantly reducing movement time, error rate, and input device footprint in comparison to the 3D point cursor.”
© All rights reserved Grossman and Balakrishnan and/or ACM Press
Bezerianos, Anastasia, Dragicevic, Pierre and Balakrishnan, Ravin (2006): Mnemonic rendering: an image-based approach for exposing hidden changes in dynamic displays. In: Proceedings of the ACM Symposium on User Interface Software and Technology 2006. pp. 159-168.
“Managing large amounts of dynamic visual information involves understanding changes happening out of the user's sight. In this paper, we show how current software does not adequately support users in this task, and motivate the need for a more general approach. We propose an image-based storage, visualization, and implicit interaction paradigm called mnemonic rendering that provides better support for handling visual changes. Once implemented on a system, mnemonic rendering techniques can benefit all applications. We explore its rich design space and discuss its expected benefits as well as limitations based on feedback from users of a small-screen and a wall-size prototype.”
© All rights reserved Bezerianos et al. and/or ACM Press
Forlines, Clifton, Vogel, Daniel and Balakrishnan, Ravin (2006): HybridPointing: fluid switching between absolute and relative pointing with a direct input device. In: Proceedings of the ACM Symposium on User Interface Software and Technology 2006. pp. 211-220.
“We present HybridPointing, a technique that lets users easily switch between absolute and relative pointing with a direct input device such as a pen. Our design includes a new graphical element, the Trailing Widget, which remains "close at hand" but does not interfere with normal cursor operation. The use of visual feedback to aid the user's understanding of input state is discussed, and several novel visual aids are presented. An experiment conducted on a large, wall-sized display validates the benefits of HybridPointing under certain conditions. We also discuss other situations in which HybridPointing may be useful. Finally, we present an extension to our technique that allows for switching between absolute and relative input in the middle of a single drag-operation.”
© All rights reserved Forlines et al. and/or ACM Press
Cao, Xiang and Balakrishnan, Ravin (2006): Interacting with dynamically defined information spaces using a handheld projector and a pen. In: Proceedings of the ACM Symposium on User Interface Software and Technology 2006. pp. 225-234.
“The recent trend towards miniaturization of projection technology indicates that handheld devices will soon have the ability to project information onto any surface, thus enabling interfaces that are not possible with current handhelds. We explore the design space of dynamically defining and interacting with multiple virtual information spaces embedded in a physical environment using a handheld projector and a passive pen tracked in 3D. We develop techniques for defining and interacting with these spaces, and explore usage scenarios.”
© All rights reserved Cao and Balakrishnan and/or ACM Press
Wigdor, Daniel, Leigh, Darren, Forlines, Clifton, Shipman, Samuel, Barnwell, John, Balakrishnan, Ravin and Shen, Chia (2006): Under the table interaction. In: Proceedings of the ACM Symposium on User Interface Software and Technology 2006. pp. 259-268.
“We explore the design space of a two-sided interactive touch table, designed to receive touch input from both the top and bottom surfaces of the table. By combining two registered touch surfaces, we are able to offer a new dimension of input for co-located collaborative groupware. This design accomplishes the goal of increasing the relative size of the input area of a touch table while maintaining its direct-touch input paradigm. We describe the interaction properties of this two-sided touch table, report the results of a controlled experiment examining the precision of user touches to the underside of the table, and a series of application scenarios we developed for use on inverted and two-sided tables. Finally, we present a list of design recommendations based on our experiences and observations with inverted and two-sided tables.”
© All rights reserved Wigdor et al. and/or ACM Press
Wu, Mike, Shen, Chia, Ryall, Kathy, Forlines, Clifton and Balakrishnan, Ravin (2006): Gesture Registration, Relaxation, and Reuse for Multi-Point Direct-Touch Surfaces. In: First IEEE International Workshop on Horizontal Interactive Human-Computer Systems Tabletop 2006 5-7 January, 2006, Adelaide, Australia. pp. 185-192.
Grossman, Tovi and Balakrishnan, Ravin (2006): An evaluation of depth perception on volumetric displays. In: Celentano, Augusto (ed.) AVI 2006 - Proceedings of the working conference on Advanced visual interfaces May 23-26, 2006, Venezia, Italy. pp. 193-200.
Wigdor, Daniel, Shen, Chia, Forlines, Clifton and Balakrishnan, Ravin (2006): Table-centric interactive spaces for real-time collaboration. In: Celentano, Augusto (ed.) AVI 2006 - Proceedings of the working conference on Advanced visual interfaces May 23-26, 2006, Venezia, Italy. pp. 103-107.
Vogel, Daniel and Balakrishnan, Ravin (2005): Distant freehand pointing and clicking on very large, high resolution displays. In: Proceedings of the 2005 ACM Symposium on User Interface Software and Technology 2005. pp. 33-42.
“We explore the design space of freehand pointing and clicking interaction with very large high resolution displays from a distance. Three techniques for gestural pointing and two for clicking are developed and evaluated. In addition, we present subtle auditory and visual feedback techniques to compensate for the lack of kinesthetic feedback in freehand interaction, and to promote learning and use of appropriate postures.”
© All rights reserved Vogel and Balakrishnan and/or ACM Press
Malik, Shahzad, Ranjan, Abhishek and Balakrishnan, Ravin (2005): Interacting with large displays from a distance with vision-tracked multi-finger gestural input. In: Proceedings of the 2005 ACM Symposium on User Interface Software and Technology 2005. pp. 43-52.
“We explore the idea of using vision-based hand tracking over a constrained tabletop surface area to perform multi-finger and whole-hand gestural interactions with large displays from a distance. We develop bimanual techniques to support a variety of asymmetric and symmetric interactions, including fast targeting and navigation to all parts of a large display from the comfort of a desk and chair, as well as techniques that exploit the ability of the vision-based hand tracking system to provide multi-finger identification and full 2D hand segmentation. We also posit a design that allows for handling multiple concurrent users.”
© All rights reserved Malik et al. and/or ACM Press
Forlines, Clifton, Balakrishnan, Ravin, Beardsley, Paul, Baar, Jeroen van and Raskar, Ramesh (2005): Zoom-and-pick: facilitating visual zooming and precision pointing with interactive handheld projectors. In: Proceedings of the 2005 ACM Symposium on User Interface Software and Technology 2005. pp. 73-82.
“Designing interfaces for interactive handheld projectors is an exiting new area of research that is currently limited by two problems: hand jitter resulting in poor input control, and possible reduction of image resolution due to the needs of image stabilization and warping algorithms. We present the design and evaluation of a new interaction technique, called zoom-and-pick, that addresses both problems by allowing the user to fluidly zoom in on areas of interest and make accurate target selections. Subtle design features of zoom-and-pick enable pixel-accurate pointing, which is not possible in most freehand interaction techniques. Our evaluation results indicate that zoom-and-pick is significantly more accurate than the standard pointing technique described in our previous work.”
© All rights reserved Forlines et al. and/or ACM Press
Ramos, Gonzalo and Balakrishnan, Ravin (2005): Zliding: fluid zooming and sliding for high precision parameter manipulation. In: Proceedings of the 2005 ACM Symposium on User Interface Software and Technology 2005. pp. 143-152.
“High precision parameter manipulation tasks typically require adjustment of the scale of manipulation in addition to the parameter itself. This paper introduces the notion of Zoom Sliding, or Zliding, for fluid integrated manipulation of scale (zooming) via pressure input while parameter manipulation within that scale is achieved via x-y cursor movement (sliding). We also present the Zlider (Figure 1), a widget that instantiates the Zliding concept. We experimentally evaluate three different input techniques for use with the Zlider in conjunction with a stylus for x-y cursor positioning, in a high accuracy zoom and select task. Our results marginally favor the stylus with integrated isometric pressure sensing tip over bimanual techniques which separate zooming and sliding controls over the two hands. We discuss the implications of our results and present further designs that make use of Zliding.”
© All rights reserved Ramos and Balakrishnan and/or ACM Press
Cao, Xiang and Balakrishnan, Ravin (2005): Evaluation of an on-line adaptive gesture interface with command prediction. In: Graphics Interface 2005 May 9-11, 2005, Victoria, British Columbia, Canada. pp. 187-194.
“We present an evaluation of a hybrid gesture interface framework that combines on-line adaptive gesture recognition with a command predictor. Machine learning techniques enable on-line adaptation to differences in users' input patterns when making gestures, and exploit regularities in command sequences to improve recognition performance. A prototype using 2D single-stroke gestures was implemented with a minimally intrusive user interface for on-line re-training. Results of a controlled user experiment show that the hybrid adaptive system significantly improved overall gesture recognition performance, and reduced users' need to practice making the gestures before achieving good results.”
© All rights reserved Cao and Balakrishnan and/or their publisher
Grossman, Tovi and Balakrishnan, Ravin (2005): The bubble cursor: enhancing target acquisition by dynamic resizing of the cursor's activation area. In: Proceedings of ACM CHI 2005 Conference on Human Factors in Computing Systems 2005. pp. 281-290.
“We present the bubble cursor - a new target acquisition technique based on area cursors. The bubble cursor improves upon area cursors by dynamically resizing its activation area depending on the proximity of surrounding targets, such that only one target is selectable at any time. We also present two controlled experiments that evaluate bubble cursor performance in 1D and 2D target acquisition tasks, in complex situations with multiple targets of varying layout densities. Results show that the bubble cursor significantly outperforms the point cursor and the object pointing technique [7], and that bubble cursor performance can be accurately modeled and predicted using Fitts' law.”
© All rights reserved Grossman and Balakrishnan and/or ACM Press
Bezerianos, Anastasia and Balakrishnan, Ravin (2005): The vacuum: facilitating the manipulation of distant objects. In: Proceedings of ACM CHI 2005 Conference on Human Factors in Computing Systems 2005. pp. 361-370.
“We present the design and evaluation of the vacuum, a new interaction technique that enables quick access to items on areas of a large display that are difficult for a user to reach without significant physical movement. The vacuum is a circular widget with a user controllable arc of influence that is centered at the widget's point of invocation and spans out to the edges of the display. Far away objects residing inside this influence arc are brought closer to the widget's centre in the form of proxies that can be manipulated in lieu of the original. We conducted two experiments which compare the vacuum to direct picking and an existing technique called drag-and-pick [2]. Results show that the vacuum outperforms existing techniques when selecting multiple targets in a sequence, performs similarly to existing techniques when selecting single targets located moderately far away, and slightly worse with single targets located very far away in the presence of distracter targets along the path.”
© All rights reserved Bezerianos and Balakrishnan and/or ACM Press
Bezerianos, Anastasia and Balakrishnan, Ravin (2005): Canvas Portals: View and Space Management on Large Displays.. In IEEE Computer Graphics & Applications, Special Issue on Applications of Large Displays, 25 (4) pp. 34-43.
McGuffin, Michael J. and Balakrishnan, Ravin (2005): Interactive Visualization of Genealogical Graphs. In: InfoVis 2005 - IEEE Symposium on Information Visualization 23-25 October, 2005, Minneapolis, MN, USA. p. 3.
Bezerianos, Anastasia and Balakrishnan, Ravin (2005): View and Space Management on Large Displays. In IEEE Computer Graphics and Applications, 25 (4) pp. 34-43.
Wigdor, Daniel and Balakrishnan, Ravin (2004): A comparison of consecutive and concurrent input text entry techniques for mobile phones. In: Dykstra-Erickson, Elizabeth and Tscheligi, Manfred (eds.) Proceedings of ACM CHI 2004 Conference on Human Factors in Computing Systems April 24-29, 2004, Vienna, Austria. pp. 81-88.
“The numeric keypads on mobile phones generally consist of 12 keys (0-9, *, #). Ambiguity arises when the 36-character alpha-numeric English alphabet is mapped onto this smaller number of keys. In this paper, we first present a taxonomy of the various techniques for resolving this ambiguity, dividing them into techniques that use consecutive actions to first select a character grouping and then a character from within that grouping, and those that use concurrent actions to achieve the same end. We then present the design and implementation of a chording approach to text entry that uses concurrent key presses. We conducted a controlled experiment that compared this chording technique to one-handed and two-handed versions of the commonly used MultiTap technique. The results show that the concurrent chording technique significantly outperforms both versions of the consecutive action MultiTap technique.”
© All rights reserved Wigdor and Balakrishnan and/or ACM Press
Grossman, Tovi and Balakrishnan, Ravin (2004): Pointing at trivariate targets in 3D environments. In: Dykstra-Erickson, Elizabeth and Tscheligi, Manfred (eds.) Proceedings of ACM CHI 2004 Conference on Human Factors in Computing Systems April 24-29, 2004, Vienna, Austria. pp. 447-454.
“We investigate pointing in true 3D environments where the target size varies in three spatial dimensions. We also study the effect of the user's physical movement angle on pointing performance. Results show that target size dimension along the primary axis of movement has a greater impact on performance than the other two dimensions. Movement angle also significantly affects performance, and changes the relative impact of the three target dimensions. Building upon recent results in the modeling of bivariate pointing, we propose and validate a new model that describes pointing at trivariate targets. This model also accounts for movement angle, and outperforms previously published models.”
© All rights reserved Grossman and Balakrishnan and/or ACM Press
Ramos, Gonzalo, Boulos, Matthew and Balakrishnan, Ravin (2004): Pressure widgets. In: Dykstra-Erickson, Elizabeth and Tscheligi, Manfred (eds.) Proceedings of ACM CHI 2004 Conference on Human Factors in Computing Systems April 24-29, 2004, Vienna, Austria. pp. 487-494.
“Current user interface widgets typically assume that the input device can only provide x-y position and binary button press information. Other inputs such as the continuous pressure data provided by styluses on tablets are rarely used. We explore the design space of using the continuous pressure sensing capabilities of styluses to operate multi-state widgets. We present the results of a controlled experiment that investigates human ability to perform discrete target selection tasks by varying a stylus' pressure, with full or partial visual feedback. The experiment also considers different techniques for confirming selection once the target is acquired. Based on the experimental results, we discuss implications for the design of pressure sensitive widgets. A taxonomy of pressure widgets is presented, along with a set of initial concept sketches of various pressure widget designs.”
© All rights reserved Ramos et al. and/or ACM Press
Tsang, Steve, Balakrishnan, Ravin, Singh, Karan and Ranjan, Abhishek (2004): A suggestive interface for image guided 3D sketching. In: Dykstra-Erickson, Elizabeth and Tscheligi, Manfred (eds.) Proceedings of ACM CHI 2004 Conference on Human Factors in Computing Systems April 24-29, 2004, Vienna, Austria. pp. 591-598.
“We present an image guided pen-based suggestive interface for sketching 3D wireframe models. Rather than starting from a blank canvas, existing 2D images of similar objects serve as a guide to the user. Image based filters enable attraction, smoothing, and resampling of input curves, and allows for their selective application using pinning and gluing techniques. New input strokes also invoke suggestions of relevant geometry that can be used, reducing the need to explicitly draw all parts of the new model. All suggestions appear in-place with the model being built, in the user's focal attention space. A curve matching algorithm seamlessly augments basic suggestions with more complex ones from a database populated with previously used geometry. The interface also incorporates gestural command input, and interaction techniques for camera controls that enable smooth transitions between orthographic and perspective views.”
© All rights reserved Tsang et al. and/or ACM Press
Zhao, Shengdong and Balakrishnan, Ravin (2004): Simple vs. compound mark hierarchical marking menus. In: Proceedings of the 2004 ACM Symposium on User Interface Software and Technology 2004. pp. 33-42.
“We present a variant of hierarchical marking menus where items are selected using a series of inflection-free simple marks, rather than the single \"zig-zag\" compound mark used in the traditional design. Theoretical analysis indicates that this simple mark approach has the potential to significantly increase the number of items in a marking menu that can be selected efficiently and accurately. A user experiment is presented that compares the simple and compound mark techniques. Results show that the simple mark technique allows for significantly more accurate and faster menu selections overall, but most importantly also in menus with a large number of items where performance of the compound mark technique is particularly poor. The simple mark technique also requires significantly less physical input space to perform the selections, making it particularly suitable for small footprint pen-based input devices. Visual design alternatives are also discussed.”
© All rights reserved Zhao and Balakrishnan and/or ACM Press
Grossman, Tovi, Wigdor, Daniel and Balakrishnan, Ravin (2004): Multi-finger gestural interaction with 3d volumetric displays. In: Proceedings of the 2004 ACM Symposium on User Interface Software and Technology 2004. pp. 61-70.
“Volumetric displays provide interesting opportunities and challenges for 3D interaction and visualization, particularly when used in a highly interactive manner. We explore this area through the design and implementation of techniques for interactive direct manipulation of objects with a 3D volumetric display. Motion tracking of the user\'s fingers provides for direct gestural interaction with the virtual objects, through manipulations on and around the display\'s hemispheric enclosure. Our techniques leverage the unique features of volumetric displays, including a 360{deg} viewing volume that enables manipulation from any viewpoint around the display, as well as natural and accurate perception of true depth information in the displayed 3D scene. We demonstrate our techniques within a prototype 3D geometric model building application.”
© All rights reserved Grossman et al. and/or ACM Press
Vogel, Daniel and Balakrishnan, Ravin (2004): Interactive public ambient displays: transitioning from implicit to explicit, public to personal, interaction with multiple users. In: Proceedings of the 2004 ACM Symposium on User Interface Software and Technology 2004. pp. 137-146.
“We develop design principles and an interaction framework for sharable, interactive public ambient displays that support the transition from implicit to explicit interaction with both public and personal information. A prototype system implementation that embodies these design principles is described. We use novel display and interaction techniques such as simple hand gestures and touch screen input for explicit interaction and contextual body orientation and position cues for implicit interaction. Techniques are presented for subtle notification, self-revealing help, privacy controls, and shared use by multiple people each in their own context. Initial user feedback is also presented, and future directions discussed.”
© All rights reserved Vogel and Balakrishnan and/or ACM Press
Balakrishnan, Ravin (2004): "Beating" Fitts' law: virtual enhancements for pointing facilitation. In International Journal of Human-Computer Studies, 61 (6) pp. 857-874.
“We survey recent research into new techniques for artificially facilitating pointing at targets in graphical user interfaces. While pointing in the physical world is governed by Fitts' law and constrained by physical laws, pointing in the virtual world does not necessarily have to abide by the same constraints, opening the possibility for "beating" Fitts' law with the aid of the computer by artificially reducing the target distance, increasing the target width, or both. The survey suggests that while the techniques developed to date are promising, particularly when applied to the selection of single isolated targets, many of them do not scale well to the common situation in graphical user interfaces where multiple targets are located in close proximity.”
© All rights reserved Balakrishnan and/or Academic Press
Aboelsaadat, W. and Balakrishnan, Ravin (2004): An Empirical Comparison of Transparency on One and Two Layer Displays. In: Proceedings of the HCI04 Conference on People and Computers XVIII 2004. pp. 53-68.
Tsang, Michael, Morris, Nigel and Balakrishnan, Ravin (2004): Temporal Thumbnails: rapid visualization of time-based viewing data. In: Costabile, Maria Francesca (ed.) AVI 2004 - Proceedings of the working conference on Advanced visual interfaces May 25-28, 2004, Gallipoli, Italy. pp. 175-178.
McGuffin, Michael J., Davison, Gord and Balakrishnan, Ravin (2004): Expand-Ahead: A Space-Filling Strategy for Browsing Trees. In: InfoVis 2004 - 10th IEEE Symposium on Information Visualization 10-12 October, 2004, Austin, TX, USA. pp. 119-126.
Grossman, Tovi, Balakrishnan, Ravin and Singh, Karan (2003): An interface for creating and manipulating curves using a high degree-of-freedom curve input device. In: Cockton, Gilbert and Korhonen, Panu (eds.) Proceedings of the ACM CHI 2003 Human Factors in Computing Systems Conference April 5-10, 2003, Ft. Lauderdale, Florida, USA. pp. 185-192.
Wigdor, Daniel and Balakrishnan, Ravin (2003): TiltText: using tilt for text input to mobile phones. In: Proceedings of the 16th annural ACM Symposium on User Interface Software and Technology November, 2-5, 2003, Vancouver, Canada. pp. 81-90.
“TiltText, a new technique for entering text into a mobile phone is
described. The standard 12-button text entry keypad of a mobile phone forces
ambiguity when the 26- letter Roman alphabet is mapped in the traditional
manner onto keys 2-9. The TiltText technique uses the orientation of the phone
to resolve this ambiguity, by tilting the phone in one of four directions to
choose which character on a particular key to enter. We first discuss
implementation strategies, and then present the results of a controlled
experiment comparing TiltText to MultiTap, the most common text entry
technique. The experiment included 10 participants who each entered a total of
640 phrases of text chosen from a standard corpus, over a period of about five
hours. The results show that text entry speed including correction for errors
using TiltText was 23% faster than MultiTap by the end of the experiment,
despite a higher error rate for TiltText. TiltText is thus amongst the fastest
known language-independent techniques for entering text into mobile phones.”
© All rights reserved Wigdor and Balakrishnan and/or ACM Press
Ramos, Gonzalo and Balakrishnan, Ravin (2003): Fluid interaction techniques for the control and annotation of digital video. In: Proceedings of the 16th annural ACM Symposium on User Interface Software and Technology November, 2-5, 2003, Vancouver, Canada. pp. 105-114.
“We explore a variety of interaction and visualization techniques for fluid
navigation, segmentation, linking, and annotation of digital videos. These
techniques are developed within a concept prototype called LEAN that is
designed for use with pressure-sensitive digitizer tablets. These techniques
include a transient position+velocity widget that allows users not only to move
around a point of interest on a video, but also to rewind or fast forward at a
controlled variable speed. We also present a new variation of fish-eye views
called twist-lens, and incorporate this into a position control slider designed
for the effective navigation and viewing of large sequences of video frames. We
also explore a new style of widgets that exploit the use of the pen's
pressure-sensing capability, increasing the input vocabulary available to the
user. Finally, we elaborate on how annotations referring to objects that are
temporal in nature, such as video, may be thought of as links, and fluidly
constructed, visualized and navigated.”
© All rights reserved Ramos and Balakrishnan and/or ACM Press
Cao, Xiang and Balakrishnan, Ravin (2003): VisionWand: interaction techniques for large displays using a passive wand tracked in 3D. In: Proceedings of the 16th annural ACM Symposium on User Interface Software and Technology November, 2-5, 2003, Vancouver, Canada. pp. 173-182.
“A passive wand tracked in 3D using computer vision techniques is explored as
a new input mechanism for interacting with large displays. We demonstrate a
variety of interaction techniques that exploit the affordances of the wand,
resulting in an effective interface for large scale interaction. The lack of
any buttons or other electronics on the wand presents a challenge that we
address by developing a set of postures and gestures to track state and enable
command input. We also describe the use of multiple wands, and posit designs
for more complex wands in the future.”
© All rights reserved Cao and Balakrishnan and/or ACM Press
Wu, Mike and Balakrishnan, Ravin (2003): Multi-finger and whole hand gestural interaction techniques for multi-user tabletop displays. In: Proceedings of the 16th annural ACM Symposium on User Interface Software and Technology November, 2-5, 2003, Vancouver, Canada. pp. 193-202.
“Recent advances in sensing technology have enabled a new generation of
tabletop displays that can sense multiple points of input from several users
simultaneously. However, apart from a few demonstration techniques [17],
current user interfaces do not take advantage of this increased input
bandwidth. We present a variety of multifinger and whole hand gestural
interaction techniques for these displays that leverage and extend the types of
actions that people perform when interacting on real physical tabletops. Apart
from gestural input techniques, we also explore interaction and visualization
techniques for supporting shared spaces, awareness, and privacy. These
techniques are demonstrated within a prototype room furniture layout
application, called RoomPlanner.”
© All rights reserved Wu and Balakrishnan and/or ACM Press
McGuffin, Michael J., Tancau, Liviu and Balakrishnan, Ravin (2003): Using Deformations for Browsing Volumetric Data. In: Turk, Greg, Wijk, Jarke J. van and II, Robert J. Moorhead (eds.) 14th IEEE Visualization 2003 Conference VIS 2003 19-24 October, 2003, Seattle, WA, USA. pp. 401-408.
McGuffin, Michael and Balakrishnan, Ravin (2002): Acquisition of expanding targets. In: Terveen, Loren (ed.) Proceedings of the ACM CHI 2002 Conference on Human Factors in Computing Systems Conference April 20-25, 2002, Minneapolis, Minnesota. pp. 57-64.
Grossman, Tovi, Balakrishnan, Ravin, Kurtenbach, Gordon, Fitzmaurice, George W., Khan, Azam and Buxton, Bill (2002): Creating principal 3D curves with digital tape drawing. In: Terveen, Loren (ed.) Proceedings of the ACM CHI 2002 Conference on Human Factors in Computing Systems Conference April 20-25, 2002, Minneapolis, Minnesota. pp. 121-128.
Burtnyk, Nicholas, Khan, Azam, Fitzmaurice, George W., Balakrishnan, Ravin and Kurtenbach, Gordon (2002): StyleCam: interactive stylized 3D navigation using integrated spatial & temporal controls. In: Beaudouin-Lafon, Michel (ed.) Proceedings of the 15th annual ACM symposium on User interface software and technology October 27-30, 2002, Paris, France. pp. 101-110.
“This paper describes StyleCam, an approach for authoring 3D viewing
experiences that incorporate stylistic elements that are not available in
typical 3D viewers. A key aspect of StyleCam is that it allows the author to
significantly tailor what the user sees and when they see it. The resulting
viewing experience can approach the visual richness and pacing of highly
authored visual content such as television commercials or feature films. At the
same time, StyleCam allows for a satisfying level of interactivity while
avoiding the problems inherent in using unconstrained camera models. The main
components of StyleCam are camera surfaces which spatially constrain the
viewing camera; animation clips that allow for visually appealing transitions
between different camera surfaces; and a simple, unified, interaction technique
that permits the user to seamlessly and continuously move between
spatial-control of the camera and temporal-control of the animated transitions.
Further, the user's focus of attention is always kept on the content, and not
on extraneous interface widgets. In addition to describing the conceptual model
of StyleCam, its current implementation, and an example authored experience, we
also present the results of an evaluation involving real users.”
© All rights reserved Burtnyk et al. and/or ACM Press
Balakrishnan, Ravin, Fitzmaurice, George W. and Kurtenbach, Gordon (2001): User Interfaces for Volumetric Displays. In IEEE Computer, 34 (3) pp. 37-45.
Grossman, Tovi, Balakrishnan, Ravin, Kurtenbach, Gordon, Fitzmaurice, George W., Khan, Azam and Buxton, William (2001): Interaction techniques for 3D modeling on large displays. In: SI3D 2001 2001. pp. 17-23.
Balakrishnan, Ravin and Hinckley, Ken (2000): Symmetric Bimanual Interaction. In: Turner, Thea, Szwillus, Gerd, Czerwinski, Mary, Peterno, Fabio and Pemberton, Steven (eds.) Proceedings of the ACM CHI 2000 Human Factors in Computing Systems Conference April 1-6, 2000, The Hague, The Netherlands. pp. 33-40.
“We present experimental work that explores the factors governing symmetric bimanual interaction in a two-handed task that requires the user to track a pair of targets, one target with each hand. A symmetric bimanual task is a two-handed task in which each hand is assigned an identical role. In this context, we explore three main experimental factors. We vary the distance between the pair of targets to track: as the targets become further apart, visual diversion increases, forcing the user to divide attention between the two targets. We also vary the demands of the task by using both a slow and a fast tracking speed. Finally, we explore visual integration of sub-tasks: in one condition, the two targets to track are connected by a line segment which visually links the targets, while in the other condition there is no connecting line. Our results indicate that all three experimental factors affect the degree of parallelism, which we quantify using a new metric of bimanual parallelism. However, differences in tracking error between the two hands are affected only by the visual integration factor.”
© All rights reserved Balakrishnan and Hinckley and/or ACM Press
Buxton, William, Fitzmaurice, George W., Balakrishnan, Ravin and Kurtenbach, Gordon (2000): Large Displays in Automotive Design. In IEEE Computer Graphics and Applications, 20 (4) pp. 68-75.
Balakrishnan, Ravin and Kurtenbach, Gordon (1999): Exploring Bimanual Camera Control and Object Manipulation in 3D Graphics Interfaces. In: Altom, Mark W. and Williams, Marian G. (eds.) Proceedings of the ACM CHI 99 Human Factors in Computing Systems Conference May 15-20, 1999, Pittsburgh, Pennsylvania. pp. 56-63.
“We explore the use of the non-dominant hand to control a virtual camera while the dominant hand performs other tasks in a virtual 3D scene. Two experiments and an informal study are presented which evaluate this interaction style by comparing it to the status-quo unimanual interaction. In the first experiment, we find that for a target selection task, performance using the bimanual technique was 20% faster. Experiment 2 compared performance in a more complicated object docking task. Performance advantages are shown, however, only after practice. Free-form 3D painting was explored in the user study. In both experiments and in the user study participants strongly preferred the bimanual technique. The results also indicate that user preferences concerning bimanual interaction may be driven by factors other than simple time-motion performance advantages.”
© All rights reserved Balakrishnan and Kurtenbach and/or ACM Press
Fitzmaurice, George W., Balakrishnan, Ravin, Kurtenbach, Gordon and Buxton, Bill (1999): An Exploration into Supporting Artwork Orientation in the User Interface. In: Altom, Mark W. and Williams, Marian G. (eds.) Proceedings of the ACM CHI 99 Human Factors in Computing Systems Conference May 15-20, 1999, Pittsburgh, Pennsylvania. pp. 167-174.
“Rotating a piece of paper while drawing is an integral and almost subconscious part of drawing with pencil and paper. In a similar manner, the advent of lightweight pen-based computers allow digital artwork to be rotated while drawing by rotating the entire computer. Given this type of manipulation we explore the implications for the user interface to support artwork orientation. First we describe an exploratory study to further motivate our work and characterize how artwork is manipulated while drawing. After presenting some possible UI approaches to support artwork orientation, we define a new solution called a rotating user interface (RUIs). We then discuss design issues and requirements for RUIs based on our exploratory study.”
© All rights reserved Fitzmaurice et al. and/or ACM Press
Balakrishnan, Ravin, Fitzmaurice, George W., Kurtenbach, Gordon and Buxton, Bill (1999): Digital Tape Drawing. In: Zanden, Brad Vander and Marks, Joe (eds.) Proceedings of the 12th annual ACM symposium on User interface software and technology November 07 - 10, 1999, Asheville, North Carolina, United States. pp. 161-169.
“Tape drawing is the art of creating sketches on large scale upright surfaces using black photographic tape. Typically used in the automotive industry, it is an important part of the automotive design process that is currently not computerized. We analyze and describe the unique aspects of tape drawing, and use this knowledge to design and implement a digital tape drawing system. Our system retains the fundamental interaction and visual affordances of the traditional media while leveraging the power of the digital media. Aside from the practical aspect of our work, the interaction techniques developed have interesting implications for current theories of human bimanual interaction.”
© All rights reserved Balakrishnan et al. and/or ACM Press
Balakrishnan, Ravin and Hinckley, Ken (1999): The Role of Kinesthetic Reference Frames in Two-Handed Input Performance. In: Zanden, Brad Vander and Marks, Joe (eds.) Proceedings of the 12th annual ACM symposium on User interface software and technology November 07 - 10, 1999, Asheville, North Carolina, United States. pp. 171-178.
“We present experimental work which explores how the match (or mismatch) between the input space of the hands and the output space of a graphical display influences two-handed input performance. During interaction with computers, a direct correspondence between the input and output spaces is often lacking. Not only are the hands disjoint from the display space, but the reference frames of the hands may in fact be disjoint from one another if two separate input devices (e.g. two mice) are used for two-handed input. In general, we refer to the workspace and origin within which the hands operate as kinesthetic reference frames. Our goal is to better understand how an interface designer's choice of kinesthetic reference frames influences a user's ability to coordinate two-handed movements, and to explore how the answer to this question may depend on the availability of visual feedback. Understanding this issue has implications for the design of two-handed interaction techniques and input devices, as well as for the reference principle of Guiard's Kinematic Chain model of human bimanual action. Our results suggest that the Guiard reference principle is robust with respect to variances in the kinesthetic reference frames as long as appropriate visual feedback is present.”
© All rights reserved Balakrishnan and Hinckley and/or ACM Press
Fitzmaurice, George W., Balakrishnan, Ravin and Kurtenbach, Gordon (1999): Sampling, Synthesis, and Input Devices. In Communications of the ACM, 42 (8) pp. 54-63.
Balakrishnan, Ravin, Fitzmaurice, George W., Kurtenbach, Gordon and Singh, Karan (1999): Exploring interactive curve and surface manipulation using a bend and twist sensitive input strip. In: SI3D 1999 1999. pp. 111-118.
Balakrishnan, Ravin and Patel, Pranay (1998): The PadMouse: Facilitating Selection and Spatial Positioning for the Non-Dominant Hand. In: Karat, Clare-Marie, Lund, Arnold, Coutaz, Joėlle and Karat, John (eds.) Proceedings of the ACM CHI 98 Human Factors in Computing Systems Conference April 18-23, 1998, Los Angeles, California. pp. 9-16.
“A new input device called the PadMouse is described and evaluated. The PadMouse consists of a two degree-of-freedom touchpad mounted on a regular mouse base. Like the regular mouse, the PadMouse allows for spatial positioning tasks to be performed by moving the device on a planar surface. In addition, when coupled with an interaction technique we call Marking Keys, users can use the touchpad to activate modifiers and commands. An experiment shows that up to 32 modifiers/commands can be quickly and accurately activated using this technique, making it a viable device for the non-dominant hand in two-handed user interfaces. Other uses for the PadMouse and design alternatives are also discussed.”
© All rights reserved Balakrishnan and Patel and/or ACM Press
Balakrishnan, Ravin and MacKenzie, I. Scott (1997): Performance Differences in the Fingers, Wrist, and Forearm in Computer Input Control. In: Pemberton, Steven (ed.) Proceedings of the ACM CHI 97 Human Factors in Computing Systems Conference March 22-27, 1997, Atlanta, Georgia. pp. 303-310.
“Recent work in computer input control has sought to maximize the use of the fingers in the operation of computer pointing devices. The main rationale is the hypothesis that the muscle groups controlling the fingers have a higher bandwidth than those controlling other segments of the human upper limb. Evidence which supports this, however, is inconclusive. We conducted an experiment to determine the relative bandwidths of the fingers, wrist, and forearm and found that the fingers do not necessarily outperform the other limb segments. Our results indicate that the bandwidth of the unsupported index finger is approximately 3.0 bits/s while the wrist and forearm have bandwidths of about 4.1 bits/s. We also show that the thumb and index finger working together in a pinch grip have an information processing rate of about 4.5 bits/s. Other factors which influence the relative performance of the different limbs in manipulation tasks are considered.”
© All rights reserved Balakrishnan and MacKenzie and/or ACM Press
Balakrishnan, Ravin, Baudel, Thomas, Kurtenbach, Gordon and Fitzmaurice, George W. (1997): The Rockin' Mouse: Integral 3D Manipulation on a Plane. In: Pemberton, Steven (ed.) Proceedings of the ACM CHI 97 Human Factors in Computing Systems Conference March 22-27, 1997, Atlanta, Georgia. pp. 311-318.
“A novel input device called the Rockin'Mouse is described and evaluated. The Rockin'Mouse is a four degree-of-freedom input device that has the same shape as a regular mouse except that the bottom of the Rockin'Mouse is rounded so that it can be tilted. This tilting can be used to control two extra degrees of freedom, thus making it suitable for manipulation in 3D environments. Like the regular mouse, the Rockin'Mouse can sense planar position and perform all the usual functions. However, in a 3D scene a regular mouse can only operate on 2 dimensions at a time and therefore manipulation in 3D requires a way to switch between dimensions. With the Rockin'Mouse, however, all the dimensions can be simultaneously controlled. In this paper we describe our design rationale behind the Rockin'Mouse, and present an experiment which compares the Rockin'Mouse to the standard mouse in a typical 3D interaction task. Our results indicate that the Rockin'Mouse is 30% faster and is a promising device for both 2D and 3D interaction.”
© All rights reserved Balakrishnan et al. and/or ACM Press
Ware, Colin and Balakrishnan, Ravin (1994): Reaching for Objects in VR Displays: Lag and Frame Rate. In ACM Transactions on Computer-Human Interaction, 1 (4) pp. 331-356.
“This article reports the results from three experimental studies of reaching behavior in a head-coupled stereo display system with a hand-tracking subsystem for object selection. It is found that lag in the head-tracking system is relatively unimportant in predicting performance, whereas lag in the hand-tracking system is critical. The effect of hand lag can be modeled by means of a variation on Fitts' Law with the measured system lag introduced as a multiplicative variable to the Fitts' Law index of difficulty. This means that relatively small lags can cause considerable degradation in performance if the targets are small. Another finding is that errors are higher for movement in and out of the screen, as compared to movements in the plane of the screen, and”
© All rights reserved Ware and Balakrishnan and/or ACM Press
Ware, Colin and Balakrishnan, Ravin (1994): Target acquisition in fish tank VR: The effects of lag and frame rate. In: Graphics Interface 94 May 18-20, 1994, Banff, Alberta, Canada. pp. 1-7.
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